A. Technical Field
The present invention relates to a process for producing (meth)acrylic acid by catalytic gas phase oxidation reaction. Specifically, the invention relates to a process for producing (meth)acrylic acid stably for a long time by allowing a reaction gas to contain a reducible compound when subjecting at least one member selected from the group consisting of (meth)acrolein, propane, and isobutane to the catalytic gas phase oxidation with a molecular-oxygen-containing gas. More specifically, the invention relates to a process for producing (meth)acrylic acid stably for a long time by stabilizing a catalyst (containing molybdenum and vanadium as essential components) by allowing a reaction gas to contain a reducible compound.
B. Background Art
(Meth)acrylic acid are industrially important as raw materials for such as various synthetic resins, paints and plasticizers. Known as the most common process for producing (meth)acrylic acid is a process which comprises the steps of subjecting propylene and isobutene to catalytic gas phase oxidation to produce (meth)acrolein and further subjecting this (meth)acrolein to catalytic gas phase oxidation to produce (meth)acrylic acid. Also known is a process in which (meth)acrylic acid are produced by one step using propane and isobutane (which are cheaper) as starting materials.
However, as to the hitherto known processes, the yield of (meth)acrylic acid is not sufficiently high, and further there are cases where the yield decreases if (meth)acrylic acid are produced for a long time.
A. Objects of the Invention
An object of the present invention is to provide a process for producing (meth)acrylic acid by which (meth)acrylic acid can be produced in a high yield in a process for producing (meth)acrylic acid by subjecting at least one member selected from the group consisting of (meth)acrolein, propane, and isobutane to catalytic gas phase oxidation with molecular oxygen or a molecular-oxygen-containing gas.
Another object of the present invention is to provide a novel process for producing (meth)acrylic acid which makes it possible to produce (meth)acrylic acid in a high yield and stably for a long time in a process for producing (meth)acrylic acid by subjecting at least one member selected from the group consisting of (meth)acrolein, propane, and isobutane to catalytic gas phase oxidation with molecular oxygen or a molecular-oxygen-containing gas.
B. Disclosure of the Invention
To solve the above problems, a process for producing (meth)acrylic acid, according to the present invention, is a process for producing (meth)acrylic acid by catalytic gas phase oxidation reaction, and is characterized by allowing a reaction gas to contain a reducible compound.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.